Manufacturing processes often require the assembly of components in very close fit relation. The tolerance requirements of any clearance space(s) between assembled components is often very small. One technique for assembling such components is by press-fit operation. This process generally requires one component to be fitted within or on another component.
The demand for press-fitting applications is prevalent in a wide variety of industries. In particular, the automobile industry uses components in press-fit applications, for example, in assembly and re-assembly processes. As the machining of individual parts has become more refined, the expected tolerance range between press-fit components has also become smaller.
Applications of press-fit operations may include, for example, press-fitting a cylindrical component onto a shaft. Another application may include press-fitting a bearing component within the orifice of a hub part. Regardless of the specific application, press-fit operations, in general, can be very useful for fitting one component within or onto another component. The aforementioned press-fit operation can be achieved by assembling separate components having very limited clearance space(s). A goal of a press-fit operation is often to achieve a final end product of assembled components while maintaining very small clearance spaces between the assembled components. Another common goal in an assembly/re-assembly processes may be to press-fit separate components together which act as a unitary product in its final assembly.
The clearances between one product and another prior to assembly are often so small as to be virtually zero. Consequently, one part is sometimes heated to expand its size to facilitate the press-fit. A heat gun and/or a heat table are typical devices used to heat a component in order to thermally expand it. A heat gun acts typically to distribute heat to a component, via a flame, in order to achieve thermal expansion. Alternatively, a heating table can be utilized to heat a side of the component by laying the component directly on the table.
Regardless of the equipment being utilized to heat the component, the heating process allows the component to expand a small amount, for example, in order for it to receive another component. Once a component is received, for example, within a receiving core of another component, the receiving core is allowed to cool. During the cooling phase, the core will shrink around the inserted component to a degree which can ultimately achieve a tight fit. This is because the clearance space between the press-fit pieces is reduced as the heated piece cools. In some applications, the cooling process can occur such that any clearance space between the two separate members becomes nearly zero. Thus separate components subjected to a press-fit operation may essentially become a unitary member.
While the use of heat guns heating tables are typically known to those of ordinary skill in the art, the use of such items contain certain disadvantages. For instance, uniform heating of a component can not generally be achieved through use of either a heat gun or heating table. This is, in part, because the component is only heated from one side using these various methods. Hence, thermal expansion is not allowed to occur evenly amongst or throughout the structure of the component. This, in effect, can produce an irregular shape in the component when it thermally expands. Such an irregular shape could ultimately affect any clearance space(s) between press-fit components such that the required tolerances would not be achieved, and hence, the assembled components would contain an assembly defect at least to some degree.
Another disadvantage of using heat guns or heating tables is that the use of such warrants a limited amount of working time to actually perform the press-fit operation once a component has been heated using these methods. Rapid cooling can occur once the thermal application of a heat source is removed from a heated component. Hence, a small window of available time exists to perform the press-fit operation and to take advantage of the thermal expansion properties of the component.
As the technology to machine components becomes more precise it is increasingly important to achieve prescribed tolerances during press-fit operations. Any irregularities between press-fit components, even on a minute level, can sometimes impinge upon whether a press-fit operation is successful. The result of assembling defective press-fit components can waste valuable resources including, for example, time, energy, and the materials of the defective product itself. The aforementioned may also translate into lost revenue consumed by processing and placing defective products.
Accordingly, a need exists therefore, for providing a method and apparatus for providing at least somewhat uniform heating to a component in order to achieve thermal expansion for use, for example, in press-fit operations.
Additionally, a need exists therefore, for providing a method and apparatus for providing a desirably long working available time of a component having a thermal expansion for use, for example, in press-fit operations.